I. Field of the Invention
The present invention relates to a signal device for use in automotive vehicles and, more particularly, to a device for providing a signal to the driver of the automotive vehicle in instances where the driver is operating the vehicle engine in an uneconomical manner.
II. Description of the Prior Art
When the load on the engine of an automotive vehicle is increased, for example, when the automotive vehicle is being driven up an incline, the vehicle driver normally depresses the accelerator foot pedal to maintain the speed of the vehicle. It is quite common that the vehicle operator will depress the accelerator foot pedal quickly under such circumstances. During this interval of speed increase the intake manifold suction decreases (that is, absolute pressure rises), and thus a rapid depression of the accelerator foot pedal to increase the fuel supply will result in an uneconomical fuel consumption and, thus, inefficient operation of the automotive vehicle engine. High engine intake manifold vacuum levels (low absolute pressure) at any given speed are necessary for good fuel economy, while low engine intake manifold levels (high absolute pressure) may be necessary for good engine performance but will necessarily result in reduced fuel economy. By maintaining the engine manifold vacuum constantly at higher levels (low absolute pressure) throughout the normal driving range, it is possible to operate an internal combustion engine at lower fuel consumption rates. In designing a system for combating the situations which result in poor fuel economy, it is important to take into consideration the poor driving techniques which generate low intake vacuum conditions and thereby result in reduced fuel economy. These techniques include the following:
A. Continuous pumping of a gas pedal while the vehicle is in a forward motion which results in numerous up-and-down changes in the vehicle speed per mile.
B. Rapid accelerations from a standing start.
C. Climbing hills or grades at increasing speeds, as indicated hereinabove.
D. Unnecessary high speed driving.
Various techniques and apparatuses have been employed in the past for providing improved systems for obtaining fuel economy in automotive vehicle engines. These systems recognize that, in the operation of an internal combustion engine of an automotive vehicle, the optimum fuel economy for any particular speed is achieved when the manifold vacuum of the engine is maintained at or above a certain level corresponding to that required to maintain that speed when the vehicle is operating on a level road. A decrease in the manifold vacuum level results in an increase in the density of the air-fuel mixture and, therefore, an increase in fuel consumption. When the operator of the vehicle presses down on the accelerator, the throttle valve of a carburetor is opened to permit a greater mass flow rate of the fuel-air mixture to the engine. This increase in the flow of the fuel-air mixture is attained with a corresponding decrease in vacuum in the engine manifold. Such a decrease in the manifold vacuum beyond the level needed to power the engine results in a higher fuel-air density and, therefore, in less fuel economy. A poor fuel economy often occurs as a result of the careless and unnecessary heavy acceleration, as described in the four examples hereinbefore mentioned. The prior art has attempted to alleviate these problems by providing systems and apparatuses which will maintain a substantially constant manifold vacuum in an automotive internal combustion engine in order to obtain optimum fuel performance or economy. These systems, while apparently operating in a satisfactory manner, tend to be complicated and costly, as they attempt to provide the desired result irrespective of the vehicle operator's operating habits. Examples of prior art apparatuses, devices, and systems which have been employed to overcome the aforementioned difficulties are disclosed in U.S. Pat. Nos. 2,148,729; 2,519,859; 2,825,418; 3,023,828; 3,158,141; and 3,250,261. While each of these patents discloses a system which provides a partial solution for the aforementioned problems, it is believed that applicant's invention discloses a new and improved system which will provide a signal to a driver in instances where he is depressing the accelerator of his vehicle more than is necessary or in too rapid a fashion to result in efficient operation of the vehicle, such that the operator may take the necessary steps to operate his vehicle in an optimum manner.